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Why is the listed sectional for KEIK Cheyenne instead of Denver?
I'm confused why a municipal airport (KEIK in Erie, CO) lists Cheyenne as its appropriate sectional, instead of Denver?
It's just over 20nm WNW of KDEN under its outer class bravo shelf and is well within the Denver TAC boundaries.  Cheyenne is 70nm to the north.
This makes no sense to me -- any help would be appreciated.

Technically, it’s in the overlap region.

Where do you see the airport listing the Cheyenne sectional?

@dwardio Is the point of your question limited to SkyVector, or are there other sources doing the same thing? If so, please link to them. If not, please understand that questions regarding why {some particular website} is doing {whatever} aren't really on-topic here.

The reason is because KEIK is withing the official region of coverage of the Cheyenne sectional. If you refer to the following chart from the Interagency Air Committee (IAC) Specifications:

A smaller version is also on the FAA website (It's a popup on the "Conterminous US" link in the second paragraph.)
As you can see, the Denver sectional coverage is 36° to 40° N latitude. Cheyenne covers 40° to 44°30' latitude. KEIK is at N40°0.61'. As @757toga mentioned KBDU is also on the Cheyenne sectional as it is also north of 40°, while KBJC is south of the parallel and on the Denver sectional.
As a bit of trivia, Baseline Road in Boulder county is so named as it is on the 40° parallel which is the survey baseline for the central US. KEIK is just north of Baseline Rd.

Thanks - that's the answer I was searching for.  I spaced on the 40N parallel being the northern boundary of the Denver Sectional.  KEIK actually borders onto Baseline (aka CO-7), btw.

EIK is depicted on both the Cheyenne and the Denver sectionals. Thus a decision must be made as to which sectional is officially referenced in the Chart Supplement entry for that airport. I do not claim to know the reason one sectional is listed instead of the other; it may be as simple as "Cheyenne" being alphabetically in front of "Denver."
Note also that pure geographic distance from the sectional's namesake is not necessarily an indication of which sectional an airport will be found on. The sectionals are named somewhat arbitrarily:

Reason for the downvote?


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How can I derive lift coefficients of wing area and horizontal stabilizers seperately from available data?
I am fairly new to aerodynamics and I am trying to create a flight simulation based on data available for F-4E Phantom.
I found various flight test data for this particular aircraft and trying to create lift coefficient slope vs AoA.

So, as far as I know, I can calculate the lift force from this for the whole aircraft. This will be sum of wing, elevator, fuselage and engine lift. Can I use wing area as reference to calculate lift coefficient? Can I use this coefficient to find tail lift force? There isn't any AoA indicator in these data, so I can't really draw the slope from this. Any direction to what can I do or what SHOULD I do will be much appreciated.

The table in the question is data in the drag axis: how much fuel is used at which speed. It looks to me like the Drag Index is a measure for external weapons configuration, if that is the case then the data at Drag Index 0 would yield the thrust required for pertaining the relevant cruise speed - if only we knew the thrust efficiency of the F-4E.
The Lift Coefficient is part of the lift equation, and lift in cruise is equal to weight. And there is nothing in the table of much relevance to lift computation.

Can I use wing area as reference to calculate lift coefficient?

Yes, all lift and drag computations use the projected wing area as a reference for lift and drag equations.

Can I use this coefficient to find tail lift force?

Finding the lift coefficient $C_L$ of the whole aircraft, and finding the lift coefficients of wing and tail separately, are 2 different things. First thing indeed could be computing aircraft $C_L = 2W / (\rho V^2 S)$. S is the wing area, which can be looked up in wiki, and $\rho$ and V follow from the data in the table.
No there is no Angle of Attack data in the above equation, for that the airfoil data $c_l$ (lower case!) is required. Plus indeed data on CoG location, moment arms, tail airfoil data etc. And sadly none of that can be derived from the table in the question.

There are 2 ways to try.  If you know where the CG is, lift coefficient of the horizontal stabilizer can be derived from the torque downforce required to maintain pitch attitude against the wing torque (around the center of gravity).
Or, you could find the airfoil type and look at the polars.
Coefficient of lift is really a combination of airfoil type and Angle of Attack.  I don't know why these are kept together, instead of being separate variables in the Lift Equation, but this is what Coefficient of lift is.
That amount to downforce (or upforce) the tail must provide is dependent on CG location.  For a F4E Phantom simulation, CG location is therefor critical, along with considerations of inertia of the jet.
The F4 has plenty of power, but is also very heavy.

That amount to downforce (or upforce) the tail must provide is dependent on CG location, yes, and on flap settings and slat position. Also, the shift in the center of pressure over Mach should significantly influence the results. Airfoil data is less of a concern, given that the F-4 is optimized for supersonic flight. That makes the airfoil awfully close to a flat plate.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


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Propulsion/ power plant
Let’s say I require 100Hp as stated by my calculations of Thrust for an aircraft-
When finding a power plant for this, would it be better to use a power plant with more Hp or exactly that 100Hp please?
I thought it would be better to use more?

If your calculations are conservative, and you're sure that 100 hp is the right amount of power for your airplane's mission, then use an engine that you are sure will provide 100 hp under the conditions (temperature, pressure) that you assumed in your calculations.
If you use an engine with more power, it will very likely be heavier and use more fuel than you originally assumed, leading to increased overall mass, requiring in turn more power, stronger structure etc.

More is better:

You'll have reserve power - engine power of standard engines reduces with altitude, no need to use a turbocharger

There will be a bit of a margin for calculation inaccuracies. It's only a calculation, only wind tunnel tests and flight tests will determine the power requirement.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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How does the TCAS decide which aircraft to climb and which to descend
In practice, how does TCAS decide which aircraft to climb and which to descend; or what factors does it take into account.

@757toga  Thank you for the reply. However, I don't think this post explains how the 'senses' (i.e. deciding which aircraft to up or down) is determined in detail

And wikipedia  also goes into it in quite a lot of detail... Suspect you'll need to read the TSO to actually determine an "exact" algorithm...

Related: In what scenario would a "climb, crossing climb" or "descend, crossing descend" be issued by a TCAS system?

Not a dupe of any single thread, and a perfectly clear (and interesting) question. VTLO

The threads linked in the comments provide an answer, but only when read in conjunction with each other.
In isolation, for a level intruder, TCAS will produce a descent - which would tell the other aircraft (via Mode-S coordination) to climb.

In case of an encounter at same altitude with a non TCAS equipped aircraft, assuming that neither climb nor descent are inhibited, the TCAS will produce a descent advisory (part 2, sec. 2.2.4.1.2.1.5 - sense selection).

What RA will be generated if intruder traffic is at our level in TCAS II?
But what if the other aircraft is "thinking" the same thing? That's the heart of this question. The answer is, whichever TCAS makes a decision first, and then in case of a tie, the lower Mode S address "wins":

When a RA is selected, it is transmitted to the other aircraft. When the other aircraft receives that message, it will only use the opposite sense {climb/descent} for its own RA. In the rare case that both aircraft transmit their RA intent at the same time, the aircraft with the higher Mode S address will give in and reverse its RA sense if it is conflicting with the other.

How does TCAS work?
For further details, go back to the threads linked here; they have good sourcing of their answers. This answer is focused on exactly the question asked here: when everything is same-same, who goes up & who goes down? In short, the aircraft with the lower Mode S address will descend.


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Why does the leading edge vortex accelerate the flow downward?
I know leading edge vortices over delta wings make more lift. I understood that the core of the vortex sheet is low, so there is suction flow that makes lift. But, I can't understand how a leading edge vortex accelerates the air downward. Please explain the detailed procedure; how does the leading edge vortex make the flow faster?

It is the inclination of the wing which forces the air flowing over it downwards. This is very much like when you hold your stretched-out hand out of a car's window and into the airstream and then slowly rotate it so it has an inclination to the flow. The vortex only makes sure that the air has enough energy to follow the wing's contour instead of separating.

how does the leading edge vortex make the flow faster?

It is suction over the top surface of the wing which accelerates the air and, due to the leading edge sweep, results in a circular motion which is superimposed on the lengthwise motion. Seen this way, it is the low pressure which produces the vortex, and the accelerated, rotating air has less static pressure, in accordance with Bernoulli's law. Trying to separate cause and effect is futile - it is all happening together.

How about it doesn't! The bound vortex does not accelerate the flow down, in 3D flow around a wing, it is the wing tip vortices that are responsible for the accelerated flow downward [1], and that imparted energy is wasted, hence why less lift and more drag is produced by a wing relative to an aerofoil.
The bound vortex is the result viscosity and is responsible for producing the Kutta condition [2]. See this great CFD video (not mine):

I will note that suction does not exist as a force, pressure can only act normal to a surface, and only inward. What we may describe as suction can always be explained as a higher pressure somewhere else [3]. That is, the pressure gradient force is always positive, it is just less in some places relative to others, and hence there will be associated forces such as lift and movement generated (you don't suck water up a straw, you reduce the pressure at the top of the straw and atmospheric pressure acting on the water pushes it down in the glass and up into the straw, similarly a vacuum cleaner does not suck air in, the compressor removes air, and the higher pressure air outside is forced in, usually bringing dust and dirt with it).
So while it is hard to separate cause and effect, it is not impossible. The actual positive pressure responsible for accelerating the air above a wing is coming from the front stagnation point. There is an asymmetric pressure gradient, which is what is responsible for making the air flow over the top surface faster, relative to the bottom surface [4].
This is all much more complex for a delta wing, where the tip vortices may not be located at the tip, if the delta wing is responsible for pitch and roll control (no canards). In this case, the downwash inducing vortices can be located inboard of the wingtips, if the wing tips have a positive coefficient of lift.

Hurt, H. H., Aerodynamics for Naval Aviators, Aviation Supplies & Academics, 1965.
Liu, T., "Evolutionary understanding of airfoil lift," Advances in Aerodynamics, Vol. 3, No. 1, 2021/12/13 2021, p. 37.  doi: 10.1186/s42774-021-00089-4
Kimbell, P. R., "Wrong...but right enough," Design and Technology Education: an International Journal, Vol. 16, No. 2,  2011. https://ojs.lboro.ac.uk/DATE/article/view/1620
McLean, D., Understanding Aerodynamics: Arguing from the Real Physics, Wiley, West Sussex, UK, 2012.


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Who is the author, or the original book of this equation to obtain an approximate ground roll take-off distance?
It's an equation to get an approximate value of the total ground take-off distance (including the distance after reaching Vr when it begins to rotate, until all wheels stop touching the ground). This is the equation that is on some lecture notes I found on the Internet:

It also specifies that in this equation, drag (D) and Lift (L) are not calculated with the maxmimum lift coefficient with surfaces in take-off configuration, but with a "typical lift coefficient" of 0.1. Drag (D) is calculated through the drag polar.

I'm not sure where you got the equation from, but it can relatively easily be deduced from the following, so really anybody with basic aerospace knowledge could have come up with it.
Acceleration: $$ a= \frac{T-D}{m}$$
Time: $$ t = \frac{V_{LOF}}{a}$$
Distance: $$ d = \frac{1}{2}at^2 = \frac{V_{LOF}^2 m}{2(T-D)}$$
And then, for some reason, the original author decided to substitute
$$ m = \frac{W}{g} $$
and $$L = W = \frac{\rho}{2} V_{LOF}^2 S C_{L_{LOF}}$$
at the point of liftoff (weight equals lift).
I simplified $(T-D)$ a bit, but it's a constant anyway, as shown in your equation, evaluated at $0.7V_{LOF}$ in take-off configuration.
The factor $1.44$ comes from $C_{L_{max}}$ being used in the denominator which is $1.2^2$ higher than $C_{L_{TO}}$ because take-off speed $V_{LOF}$ is $1.2$ higher than stall speed in take-off configuration.

Thank you very much!


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what will happens if there is a leak in air conditioning system?
In different system such as "Air cycle" and "vapor cycle" air conditioning system.

This question could be improved by adding more detail. What kind of leak in what part of the system? Why do you want to know? Are you looking for symptoms or a worst case scenario?

leaks in any part

Not sure why this is on the aviation SE. But if the leak is in the refrigerant line then refrigerant will leak out of the system leading to reduced system performance and increasing the rate of global warming.

I think that one is ozone layer no?

In a vapour cycle system, a leak means the refrigerant leaks out, and the result is the same as in a car (because the system is more or less the same).  It loses its cooling ability.
In an air cycle machine system, it depends where the leak is, and how bad it is. Because of the large volumes of air involved, usually duct joint leaks don't cause noticeable performance degradation before the bleed leak warning system detects the problem, the air going through the system being fairly hot up until the final expansion stage in the Air Cycle Machine.
A leak that doesn't get detected by the bleed leak loops, if gets large enough, will eventually get snagged by the flight crew if the crew thinks the A/C performance is unusually poor.


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Starstreak Missile system - How do the darts avoid colliding with each other?
There is plenty of detailed info online about how the individual darts fly and manoeuvre but nothing about how they maintain their triangular separation.

Good question :D, out of curiosity: Which references did you already read concerning the flight of the darts?

The darts are steered by command from the launcher, are they not?

The darts contain a Guidance and Control section which observes a 2D Laser-grid emitted by the launcher. The darts then steer themselves such that they stay in the center of this grid.

Hi thanks. I assume that the dart’s c and c system notes which grid it is in then maintains that grid posit? I found an excellent description online : https://military-history.fandom.com/wiki/Starstreak_(missile) There are also more descriptions of the rotating fore body and clutch system that controls direction just using two canards- v light and manoeuvrable system

No, I Do not think that thats is the case, simply because the grid is not rotating, but the Darts are rotating around the Center of that grid. Controlling the Darts in a Formation is (imo) unlikely because it would require very fine control. But I Do not know fore sure, hence I cannot answer This.


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Why is this commercial plane making this manoeuvre?
The plane going in circles above my head for an hour now, what could it be?

Still going: https://flightaware.com/live/flight/IAD9503

Does this answer your question? Why is this plane circling around the Lucknow airport every day?

@FreeMan Whilst I wouldnt want to see us drowned by questions showing an FR24 track with the question "Why is this plane doing this?", suggesting this is a duplicate based on the fact that they happen to both be training flights in completely different parts of the world with different aircraft is ... well..... somewhat not what duplicates are! You are of course free to suggest a duplicate any time you see fit, but just think about whether the question is the same (duplicate) or whether the answer might be similar - probably not a duplicate.


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Question on Pilot Age Limits Worldwide
ICAO have set pilot age limits for “international commercial air transport operations” as follows:
65 years old in multi-pilot operations
60 years old in single pilot operations
The US FAA and EASA apply the same rules. All ICAO states should apply the same rules.
QUESTIONS:
1. Which countries have NOT applied these rules?
I’ve seen the same list in a few places of countries which have no age limit - Australia, Brazil, Canada, Costa Rica, New Zealand, Russia, New Zealand, Senegal, Ukraine.
And then some countries which have higher age limits - Japan, China.
Are there any more countries which should be added to either of these lists?
2. These rules are for commercial air transport operations. Does that include charter flights?
Also, are there any age limit rules for private flights?
3. Who actually sets the rules for pilot age limits?
The country that issues the pilots license? The country where the aircraft is registered? Or whatever the country is that the pilot happens to be flying in?

FAA max age is 60 for both single- and multipilot flights.

@Vikki The FAA rules changed in 2007. Part 121 was raised from age 60 to age 65 for 2 pilot crew.

I don’t have a list of which countries have what age restrictions. Each country sets its own regulations for max age and the max age for each country is constantly changing.
I believe that Charter flights for large passenger aircraft have the same rules as scheduled carriers, but rules can vary from one country to another. That is one of the many reasons ICAO exists: To standardize some rules between countries.
All ICAO member countries must apply the same ICAO rules. ICAO age rules are really exceptions which allow a pilot from one country with higher age restrictions to fly to a country with lower age restrictions. Age 65 just happens to be the max ICAO age agreed to by all ICAO member countries. Any ICAO member country can have higher or lower limits for it’s own pilots.
Australia is an ICAO member, but has no maximum age for its own airline pilots. The ICAO age 65 rule does not prevent a 67 year old Australian airline pilot from flying domestically, or to another country that has no age restrictions. The only limitation for that Australian 67 year old pilot would be to avoid the airspace of other more limiting countries.
If an Australian pilot wants to fly to a country that has a regulatory max age of 62, the Australian pilot can not be older than 65 in order to take advantage of this ICAO exception.
If Australia was not a ICAO member, then the max age to fly to that age 62 country would be 62, even though Australia has no max age. It is membership in ICAO that allows outside pilots to not have to abide by more restrictive local regulations.

Thanks Mike, very helpful! That prompted me to do some research on non ICAO states - it seems like there are none! (Maybe Lichtenstein, not sure that really counts). That essentially means that under ICAO rules, all commercial pilots everywhere should be able to fly internationally up to age 65, right? (as long as it's multi-crew)

Yes, that is my understanding.


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What is a good airfoil for a throw glider
I am trying to design a free flight glider (I don't know what I'm doing, however, I'm interested in aerospace engineering and am trying to learn) And I was wondering, what would a good airfoil be? I also want to know; how much lift can something create before it begins to stall? I have calculated my CoL of the glider, I think I found the CoT, but I need help finding the right airfoil and AoA for a styrofoam glider. it currently ways around three pounds and is 14 inches (from nose to tail), and it has a flat bottom.

I'm thinking of around a 7-inch wingspan, but I can't find a good airfoil, I also think the one I want to use (Eppler E393 airfoil) may cause too much lift. I also don't know how to calculate how much thrust I will be creating when I throw the glider.

I believe free-flight gliders are normally thrown in a banked attitude to prevent the plane from trying to loop when thrown at a speed high enough that the wing generates more lift than the weight of the plane.  So the plane is launched in a turn.

Consider asking your question on a model airplane forum like "rcgroups.com" (check out the "modeling science" section there).

I’m voting to close this question because it belongs on Drones.SE, not Aviation.

How is my question a drones question?

3 pounds is VERY heavy for a glider of that size. You really ought to consider removing a large amount of that weight, especially if the wingspan will only be 7 inches.

Yes, 5-6 ounces per square foot of wing is a good number. See Mark Drela's Alegro if interested in AE. http://www.charlesriverrc.org/articles/allegrolite2m/markdrela_allegrolite2m.htm

3 pounds/14" is a missile, not a glider. At the very least, you need to specify whether you are optimising for distance or time of flight. For reference, competition gliders for time weigh under 1 lb for a wingspan over 2 m (80"). They are not thrown, but they will outcompete yours in most circumstances.

The cambered Eppler E 393 is a great choice if you are going to a hill top for a smooth slow constant speed glide.
For a throwing glider, or one that experiences change of airspeed, a thin low drag wing with lower lift coefficient is better.  This is why deltas are very popular for paper airplanes!  This is particularly true
with low wing loading.

a 14 inch glider need not weigh 3 pounds

If you want to throw like a spear for distance, reduce weight and camber, going for low drag.

throw it hard and it just loops

This is where you move your CG back and reduce nose up trim.
Ideally, you want the plane AoA to increase as it slows down.
(To keep lift the same).  It will have a flatter trajectory when thrown hard, only stalling at the very end of the flight.
Having tried both, free flight from hill tops seems better, but too much camber will not perform well in gusts either for the same reasons.


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What is a control area?
I read a controlled area is a controlled airspace extending upwards from a specified limit above the earth.
But what is the difference between a contolled airspace  and a control area.Also what about lateral limits. Also who decides the level limit...

What books are you reading?  Where will you be flying?  Your study material for the area where you plan to fly should explain all this.

Your first question can be answered directly from the definitions:

CONTROL AREA [ICAO]- A controlled airspace extending upwards from a specified limit above the earth.
CONTROLLED AIRSPACE [ICAO]- An airspace of defined dimensions within which air traffic control service is provided to IFR flights and to VFR flights in accordance with the airspace classification.
Note: Controlled airspace is a generic term which covers ATS airspace Classes A, B, C, D, and E.

The difference between controlled airspace and a control area is the difference between asphalt and a highway. Controlled airspace is the material from which a control area is constructed.
As to your second question, the local civil aviation authority and/or the air navigation service provider will determine the locally preferred configuration of a control area to provide the most beneficial service to airspace users within the limits of available resources.

please do not answer a question than not only is probably in need of closing, but that even you voted to close.


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If while landing ,a surface inversion occured close to the ground would atc or atis know?
A change in temperature, pressure and many factors might happen in a surface inversion.Thus affecting landing performance and calculation.The local peessure might change suddenly as well...

Local pressure can't change suddenly. Air is a fluid and so will equalize pressure differences. The only case major pressure difference is possible is when there is very strong wind like in a storm, hurricane or tornado, and in that case you've got much bigger problem than the pressure change.

… only the pressure gradient will change a little with temperature, but you are normally ignoring that anyway; the altimeter does not have an altitude correction.

Probably not unless a pilot reported it. METARs and TAFs only include ground temperature/pressure so presumably that's all they know.


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Which countries use qfe field pressure?
I heard that acrobatic flight, Russians, Americans use qfe but is it always the case?
Also why doesn't everyone use it?
Isn't qfe field pressure better than qnh local pressure...
Does a pilot ever use qfe or field pressure in big airplanes like airbus or boing .
I know pilots can input local pressure or standard pressure std = 1013.25 hpa ...but can they input qfe ? or not all airplanes have qfe?

reminder to put answers, however partial, in the answer field.

Also why doesn't everyone use it? Isn't qfe field pressure better than qnh local pressure...

Advantage of QFE is that it will read 0 on the field (and therefore approximately height in the pattern), so the pilot does not have to think about the runway elevation.
However a big disadvantage is that it is specific to the airfield. So when you have multiple airports near each other, you'd have aircraft flying around with different QFE settings. Which makes it work poorly for the other two purposes altitude is needed for: separation of aircraft from each other and separation from terrain. Plus it increases the risk of problems because pilot forgot to change the value.
With QNH everybody in the area will be using the same value, so everybody can be confident two aircraft reporting different altitude do indeed have different altitude. And there is one minimum safe altitude that applies to aircraft departing from and arriving to all the airports in the vicinity. The price is that the pilot has to remember the pattern and landing altitudes for that particular airport. It is a small price compared to all the risks of using QFE.

acrobatic flight

This is a notable exception. Aerobatic aircraft doing the aerobatic routine only flies in a tight show box where all other traffic is excluded, and the pilot has a lot of altitude values where he needs to initiate the various figures so he is high enough not to hit the ground and low enough that the spectators see him well. So there is makes sense to set the altimeter to read 0 at the ground, i.e. QFE, so he does not have to make any adjustments dependent on the location where he's performing.

I know pilots can input local pressure or standard pressure std = 1013.25 hpa ...but can they input qfe ? or not all airplanes have qfe?

QFE is entered the same way the QNH is entered. It is, however, possible that for high altitude airport the QFE is lower than the lowest value the altimeter will accept.

I learned PPL and IFR in the USA. QFE was briefly mentioned in training but everything else at all times was QNH. ATC always reported in QNH as did inflight and online weather services (I have seen a handful of METARS give QFE in remarks). Sectional/visual and IFR charts give all altitudes in MSL so QNH is preferred (one can calculate AGL of obstructions, mountains, etc).
On IFR approaches knowing QFE may be helpful if equipped with multiple altimeters since you often look at height above touchdown zone/runway.
I have read Russia used to use QFE (and Lat/Long coordinates) but had changed recently to QNH or offers it. A few countries like China use altitude in meters, other report airport winds in meters per second, some use flight levels at 1013 hpa etc. In USA we use degrees C instead of F for aviation yet nautical miles and feet.

Flightlevels are per Definition always measured to 1013 hPa. What’s your point?

They measure all altitudes in flight level instead of regular QNH

I never heard of that before, which countries are you referring to? I know places with TA as low as 2500ft or 3000ft, but I can’t believe it’s legal to use FL at every level.

@BobJohnson Incorrect. QNE is only used above the Transition Level. The TL in some countries may be lower than you’re used to, but it is never zero.


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Airplanes Parking On Taxiway
I've noticed one or two planes at my airport continuously park on the Taxiway and stay for sometimes an hour+. I keep looking and can't seem to find any regulations on this topic. (Only finding stuff about taxiway construction) Can someone find me something released by the FAA regarding this issue. Are they to be fined or just told "move it".

Who owns the airport?  Is there an airport manager?  This is probably best resolved at the local level.

During The Master's golf tournament one taxiway is lined with parked aircraft. Here's some shots (from the Twitter video): https://www.google.com/amp/s/www.golfdigest.com/story/masters-tournament-2022-augusta-regional-airport-private-jet-video/amp

during the covid travel restrictions and the airspace closure after 9/11 many airports had taxiways and runways used as parking space for hundreds of aircraft, often for weeks or months at a time. In some cases this actually caused problems for the structural integrity of the taxiways.


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In FOI why ACS/PTS it should be emphasized those documents are not a teaching document?
In Aviation Instructor’s handbook (FOI) they said “ACS/PTS it should be emphasized those documents are not a teaching document”Is there any reason?

Welcome.  FWIW, quotation marks are generally reserved for direct, verbatim quotes.  If you intended to paraphrase your interpretation of the handbook you should leave the marks out.  That said, did 757toga quote the section you are asking about below?  If so, your interpretation is pretty much 180 out from the intended meaning.  Just sayin', read carefully!


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LVO Operation Airbus 320
Let's say we are Cat 2 rated and shooting an approach with cat 2 weather condition. During the approach around (2000ft) , aircraft downgraded to Cat 1 single. can we continue the approach ?

I am struggling to understand the meaning of "downgraded" and "single" in this question.  Did you lose an engine, or did you lose a pilot?  Could you please expand your question just a bit, to be more user-friendly to those of us less steeped in airline-pilot lingo?  Thanks.  PS and that might include spelling out in actual words, what is the meaning of "LVO".  Is the "O" redundant with "Operation"?

so sorry :)...CAT1Single is what displyed on airbus 320 PFD when we armed approach. and my question is just what happens when aircraft had some internal failure that renders aircraft to downgraded to CAT1 Single on PFD. thank you @quietflyer

in one of UK destination @757toga

yes it is an US air carrier

(LVO = low visibility operations.). Do your company procedures prohibit you from continuing to cat I mins?  Do you have the vis for a cat I?  Because that would be the obvious best choice, right?

Just a side note: cat 1 single never shows up; dual or single only shows up in cat 3 to signal fail operational or fail passive capability; cat 1 or cat 2 show up with no single/dual indication.

Assuming you are asking in a Commercial Air Transport context, we have 2 issues here: one regulatory and one procedural.
The procedural one: you can only continue an approach below 1000ft AAL in IMC if the approach is stabilised; that means, among other things, that all checklists have been completed. So if you have a failure most likely there will be a checklist to do and in case of a landing capability downgrade, a briefing to update. You need to have all of these done by 1000ft AAL to continue.
The regulatory one: according to EASA OPS regulations (European carriers) you may only continue an approach beyond a certain point, which is 1000ft above aerodrome level for a precision approach, if the reported RVR is at or above your landing capability (being the most restrictive of crew, airport and aircraft/company). This policy is called "commencement and continuation of approach" in the legislation (see CAT.OP.MPA.305 below).
https://www.easa.europa.eu/document-library/easy-access-rules/online-publications/easy-access-rules-air-operations?page=37#_DxCrossRefBm136404587
In FAA regulations (USA) the main difference here is that the entry into the final approach segment is used instead of 1000ftAAL for the regulatory aspect.
So in this case, what you usually do is start slowing down to final approach speed (to gain some time), continue the approach and ask for updated RVR information from TWR to see if before 1000ft AAL you can get an answer which allows you to proceed to the DA/H, and then assess whether or not you have visual references to land.
Obviously you can always opt to go around immediately, enter a hold, and decide what to do, and in case of doubt it is the safest option.
Hope this answers your question.

FCOM and SOP (part B) would have precise answer to this. If weather CAT II and your DA becomes CAT I you go around.

There 2 different concepts about the issue that you asked for.
1-Downgrading
2-Single Channel
1-Downgrading is the stepping back from fail operational to fail passive. AFS permits dual A/P engagement and reflects CAT III dual on FMA. System itself is said to be fail-operational if downgrading occurs, autoland capability is still. Why downgrading occurs ? Terrain, GPS, system malfunction...
On the other hand, if the fail passive system faces a problem, it can no longer be able to provide autoland. Both of these situations are not A/P failure.
2-Dropping to single channel; you face an A/P failure and not be able to engage 2 A/P at the same time.
Result,
If you downgrade from CAT III to CAT II ( on FMA ) and system is fail-operational (fleet,A/C info) you are able to continue approach with an extra caution.
If you have an A/P failure and operating with a single one, your minima becomes CATI minima. For this occasion you need to execute go around.
Infos I mentioned here are too shallow, please read more on FCOM,SOP.
Safe flights.


text:
How to determine date of pilot license?
I wonder if someone can tell me how to find out what year my Dad got his private pilot license as well as his commercial pilot license? BC Canada
Thank you.

Canadian pilots have a 6 digit file number which is sequential. It also corresponds to the pilot licence number in most cases. It may help narrow down the year it was issued. Do you know his pilot licence number or file number?

Mine's from 1975, and the 1st 3 digits are 159.

@John K That fits because mine is from 1976 and my licence and file number is 160xxx.

Bah!  1976.  Just a youngster. lol   When did you start with Air Casual?

Not until 2000. I flew bush from 1979-1989, then Canadian Regional 1989-2000.

Unfortunately I don't know the number.  I am hoping we find his license somewhere in his things.  I was hoping also that there is a data base where one could look up his name and find out.


text:
Can a Turn and Bank Indicator be combined with a VSI?
I have found a picture of a VSI on an AN-225 that seems to have a slip indicator with another indicator above the slip indicator. May I know if the scale and the slip indicator is a turn and bank indicator?

If the picture is not enough to show that it can be, what kind of proof are you looking for?

Just looking at it that's what it appears to be; VSI+skid ball+turn and bank.  That is probably a caging knob for the gyro at the bottom. If the VSI is instantaneous reading, it would be useable for pitch control in IMC, so the instrument is probably intended as an all-in-one backup to the attitude gyro.  I've never seen one before, so can't be sure.

Are we sure the white needle is VSI? In MIG21 there is a similar instrument where the white needle is AOA if I remember correctly.

Why is the vertical needle shaped the way it is, with a long tail, some of which is painted black to hide it?  Is it possible that it is essentially just a weighted "pendulum", not connected to any internal mechanism?  If so, it not be a turn rate indicator, but rather would essentially provide the same information as the ball, but without the damping of the fluid.

From a regulatory standpoint there is no requirement in the US under 91.205 for a bank/rate of turn instrument to be combined with the skid/slip indication of the ball.  The ball could legally be combined with any instrument, as long as it is in easy sight of the pilot.


text:
Are there any relationship between lateral and directional stability?
Directional stability is affected by the side areas such as the vertical stabilizers and lateral stability is affected by dihedrals. Is there any relationship between lateral and directional stability as a roll result in a pitch and most aircraft are configured to have more lateral than directional.

For stability in roll, yes there is a direct relationship.  To achieve good stability in roll from dihedral effect, directional stability must not be too strong.
This is because dihedral effect requires sideslip to work.  But directional stability (weathervaning in yaw) tries to minimize side slip.  If the plane is bumped into slight bank while flying along, some sideslip must be allowed to develop before the weathervaning forces in yaw take effect to get the tail aligned with the nose in the airflow.
So to have good lateral stability, you need directional stability characteristics to be degraded just enough to ensure a slight lag in the directional weathervaning tendency, because it's the lag that allows a bit of sideslip to develop, which is what gets dihedral effect to work.
Tail volume calculations (area x arm) take this into account in vertical tail sizing. The vertical tail volume should be large enough to have a strong weathervaning effect, but not strong enough to prevent a small amount of initial sideslip to develop when banked by a disturbance.
If you do make the vertical tail too large, you will have fantastic directional stability as the plane instantly weathervanes into the airflow when disturbed in the yaw axis.  But without a slight lag in the weathervaning tendency following a yaw disturbance, when a lateral disturbance occurs, no side slip develops, and dihedral effect can't work.
The result is the plane becomes laterally neutrally stable, or maybe a bit unstable, as any roll disturbance that banks the plane causes it to weathervane to stay aligned in the airstream instantly, before sufficient sideslip can develop to get dihedral effect going. If you leave the airplane alone while it's doing this, you'll find that every lateral bump that causes the airplane to bank a little bit causes it to spiral toward the low wing. In other words, too much vertical tail volume causes a spiral instability or spiral diving tendency.
And obviously, too little tail volume just results in a plane that slithers around the sky and is unpleasant to ride in, and if you don't have a yaw damper, your feet have to do the job to keep the thing straight directionally.
I flew a small float plane one year doing float ratings, a Fleet 90 Canuck, that was at that other extreme of insufficient directional stability. Its certified float installation did not include an additional ventral or dorsal fin to account for the destabilizing effect of the floats (added side area forward).
Its directional stability on floats was only mildly positive, and the nose would drift all over the place in bumpy air and your feet were going constantly. But its lateral stability was great because lots of sideslip could develop when it was bumped into a bank, so its dihedral effect and lateral stability was very strong.

a roll resulting in a pitch

Yes, there is a relationship here, as a roll results in loss of vertical lift, and the plane will sink.  The sink should pitch the nose down.
But dihedral itself does not fix roll instability in a cross wind gust, in fact it makes it worse.  Dihedral must be balanced with a "keel" below the center of gravity.  This balances side force around the Center of Gravity.
If the plane is deliberately rolled, dihedral also helps it upright if the rolling input is removed and the roll is only slight.
The "book" says sideslip must develop, but sinking a little bit is enough to "activate" the righting dihedral effect.  The combination of keel (to prevent rolling in a sidewind gust) and the dihedral (to help right any unintentional roll) makes for the classic "high wing" trainer design.
Excessive directional stability in the form of a large tail does introduce "spiral instability", but remember, the torque of a tall, upright tail, especially with coordinating rudder applied, also favors a "righting", or dihedral effect.
Changing the twin tail of the B-24 Liberator to a single upright vertical fin on the PB4Y-2 Privateer greatly improved its flying characteristics.

Kudos to the story about putting floats on the Fleet 90 Canuck by John K.  It inspired this answer.  I would definitely get those ventrals on there.

"especially with coordinating rudder applied" -- can you explain what you mean by this?  For example, airplane has accidentally rolled from wings-level into a right bank.  Which direction is "coordinating rudder"?  Is pilot applying left aileron plus left rudder to roll back to level?  If so, direction of roll torque due to rudder would appear to be opposite to what you are suggesting.  It can get confusing when we combine a discussion of self-righting due to dihedral-like effects, with a discussion of "coordination", and its hard to follow exactly what you are meaning to say about the rudder.

Re "The "book" says sideslip must develop, but sinking a little bit is enough to "activate" the righting dihedral effect."-- I would question the idea that there is any relationship between sink rate and sideslip when banked.  Experiment: while turning, shove the stick or yoke forward to "unload" the wing to zero G's.  Does the slip-skid ball move?  Which way?
How much?  Maybe the basis of a new ASE question.  Or an old one:  related: https://aviation.stackexchange.com/a/93041/34686

Banking reduces vertical lift.  Any questions there?

@quietflyer for your benefit, unloading the wing in a a turn stops the turn and would cause the plane to sink.  Self righting tendency would help wings level, but would be descending.  Interesting that reducing G's on the ball might affect it, but I'd be more interested in getting level and pulling out of the dive.  And the "tall tail" actually helps more with yaw.  These things are amazingly interrelated.

"especially with coordinating rudder applied" is referring to balancing forces in design.  I just cringe hearing people needing opposite aileron to hold a bank.  This is one way of avoiding that.


text:
What type of flight plan are ZeroG experience flights?
According to flightradar24, the ZeroG experience flights are on an IFR flightplan climbing into Class A airspace. Do they file lat long fixes for the flightplans or do they use fixes to guide the flights? Are they assigned block altitudes to do the "Zero G" simulations? In this case, the aircraft is N794AJ.

An operator conducting regular operations like that will normally negotiate an operating area or areas, with the corners defined by lat/long waypoints that can be easily programmed into an FMS, with the appropriate ATC unit, with a written agreement that has the parameters and requirements clearly defined. Manufacturers use such designated test areas for production test flights, so it would be a similar situation for an operator doing ballistic arc flights.
When you do a trip into the operating area, you just file a normal IFR flight plan from the departure airport to a fix or fixes or possibly an airway that leads into the area. You may include an altitude block in your flight plan, or you may just get an initial altitude clearance for entry, and request the block once you are there.
Once in the operating area, and with a block altitude clearance, you are free to move anywhere within the lateral boundaries, and within the altitude block, without having to talk to ATC, until you're ready to leave, or unless ATC calls you to modify your clearance with some kind of restriction to accommodate traffic they want to pass through or nearby.


text:
What do air traffic controllers call themselves? Or how are ATCs referred? "Controller"? "ATC"? "Control"?
What do air traffic controllers call themselves? Or how are ATCs referred? Is it "controller"? "ATC"? "Control"? For example, if I wanted to say an airport has a shortage of air traffic controllers or if I wished to say there was a group consisting of pilots and air traffic controllers, but don't want to use the entire phrase, what can I use instead?
Thanks!

Most call their peers controllers. If you get a bunch of Type A people working next to each other, conflict sometimes arises, and their peer references can get a bit more colorful!

From the Wikipedia article on ATCOs:

Although the media in the United States frequently refers to them as
air controllers, or flight controllers, most air traffic professionals
use the term air traffic controllers, ATCOs, or controllers.

In my (limited) personal experience, ATCO seems to be popular in the UK.


text:
What does "localizer level flight" in the approach checklist mean?
What does "localizer level flight" in the approach checklist mean?
How might an actual dialogue in the cockpit sound when the approach checklist is executed? Are the words "localizer level flight" actually said aloud? If so, what is said in response to them?
I.e.

"Localizer level flight." (?)
"???"
"Fasten seat belts."
"On." (?)

Thank you!

Do you have the full checklist?  Where did you get this excerpt from?  Can you post a link or screenshot?  (most checklists delineate by font, italics, etc. what the verbal challenge and response elements are.  It would be a lot easier to decode with an example for context.)

Something like this: https://www.scribd.com/document/179167779/Boeing-737-200-Checklist

For what it's worth, that "checklist" has many severe issues and bears scant resemblance to what's actually used in 737 operations. The term "localizer level flight" isn't a standard term, and several of the items listed under that heading really need to have been accomplished long before intercepting the localizer. I'd recommend ignoring that document and finding a better source.

@RalphJ Thank you for letting me know. By any chance, do you know where I might find a more legitimate example of an approach checklist?

@RalphJ Does this look better? https://ibb.co/xFWY1cb

That looks less awful, but it's for a different aircraft, and some of the items are still pretty clumsy. What's the source of all of these documents? If they're coming from an internet search, please realize that the search engines have no judgement about quality; they'll just return things that call themselves checklists that have been linked some number of times. For something close to what Boeing recommends, see here.

The source is just me doing Google searches for different combinations of words... I don't need it to be for a particular aircraft; this is for a hobby translation/writing project, and I'm mainly just trying to figure out 4 lines of plausible dialogue of pilots going through a checklist prior to landing, preferably with one of the items on the checklist being the fasten seat belts sign.

Its the phase of flight when your established on the localizer but have not yet started your decent on the glide slope and are in level flight. In other words your utilizing the horizontal guidance component of the approach but have either not intercepted the glide slope yet or the needles are coming in and you are not yet at the point of descending. This answer has a good description of intercepting the localizer.
For example lets say your coming into KHPN on the ILS to 34. If you intercept outside of THEEO you will be straight and level but following horizontal guidance until you get to THEEO and thus will be following the localizer but in level flight.

Slight enhancement — you have levelled off and are tracking lateral guidance until you intercept the glideslope OR the next step-down fix (in the case of a localizer only approach).


text:
Does the following sound realistic as callouts during takeoff?

“Set power.”
“Power is set.”
“80 knots.”
“Check.”
“Constant power.”
“V1.”
“Rotate.”
“V2.”
“Positive rate.”
“Gear up.”

I am unsure about "Constant power." The original text I am translating from has "推力保持" lit. thrust maintain, but I couldn't find actual sample dialogue online with that particular callout (I could find everything else), so I was wondering if someone could take a look for me.
Edit: Did some more Googling - is it "Throttle hold"? Or is that not a callout?
Thank you so much!


text:
How do pilots refer to an aeronautical/aviation chart in casual terms?
How do you refer casually to an aeronautical chart? For example, in casual conversation between pilots and/or other related personnel, do you say the entire phrase? Or is it just something like "chart"?

Just Aeronautical Chart, or Map. Maybe Aviation Chart or Map if the syllable count is annoying to you.
When I was bush flying, we didn't even use Aeronautical Charts; we used Topographical Maps made by the Ontario Ministry of Natural Resources, because the 1:50,000 scale was necessary to be able to scud run from lake to lake at 400 ft AGL under a 600 ft ceiling.

The standard colloquial terms in the UK are "half mil" (1:500000) and "quarter mil" (1:250000).  See, for example this page, second paragraph of the "What do I need?" section.


text:
What might an air traffic controller say to approve a request from a pilot for a certain heading?
I'm translating something that involves radio communications dialogue.
Two questions, actually:

How would a pilot request a particular heading? (Does this ever happen?) E.g. something like "Request heading XXX"?
How would a controller respond to such a request? (In particular, the part I'm translating is an approval for the request, but I'd be interested in how a controller would deny the request too.)

Thank you!

The verbose request:

Center, Callsign123 has weather ahead. Request heading 045 for about ten miles to avoid it.

Or:

Center, Callsign123 request 10 degrees right for weather.

The minimalist request:

Callsign123 request heading 045.

ATC might reply

Callsign123, fly heading 045 and advise when you can take a turn back to course.

Or:

Callsign123, approved as requested, direct Tulsa when able.

Or:

Callsign123, unable right deviations due to military airspace, fly heading 010 and advise when able direct to Tulsa.

It may differ where you are in the world.
But a typical standard interchange you would hear around Europe would be:
“Ryanair 5XD, request heading 050 degrees due weather”
“Roger Ryanair 5XD, deviation approved, for how many miles?”
“For three zero miles, Ryanair 5XD”
“Ryanair 5XD, Roger”
Of course you only need to request headings in circumstances where you are under radar control.
Typically radar headings are only really requested for weather avoidance, if you are looking for a shortcut you may ask for direct to a waypoint which will be a shortcut.

I don't know whether that is standardized phraseology, but I sometimes hear ATC rephrasing the request as an instruction, i.e., as-if the pilot had never requested it in the first place: "FictionAir 123, request heading 050 degrees due weather" – "FictionAir 123, turn right heading 050" – "Right heading 050, FictionAir 123". The other extreme would be "FictionAir 123, approved as requested", which is generally not a good thing since there is no two-way confirmation that both stations have understood the request the same way, but it does happen.

Yes, sounds familiar


text:
How is expected approach time phrased in ATC communications?
For example, does an air traffic controller say the full phrase ("expected approach time XX minutes") or are there other conventions?

Can you provide some more context to this question? The answer may vary by jurisdiction and local regulations. Are you asking about a specific portion of the "approach" (as that may refer to multiple things). Some instrument approaches are "timed" for finding the FAF but that is dependent on aircraft size and is not communicated by ATC per-say.

Why the close vote?

An expected approach time shall be transmitted to the pilot in case holding/delay in excess of 10 minutes is expected. Phraseology:
a) No delay expected
b) Expected approach time (time)
c) Revised expected approach time (time)
d) Delay not determined (reasons)
So in your example, the praseology would be along the lines of "Expected approach time 10:42"

@757toga https://selvbetjening.trafikstyrelsen.dk/civilluftfart/Dokumenter/Ekstra%20net/ATS%20Instrukser/ATS-instruks%2014%20-%20Kommunikation.pdf

One of our controllers may give a better answer, but if an aircraft was expecting to commence an approach on arrival but is instead given holding instructions by ATC, an expected approach time, or expected further clearance time should be given in the event of lost communications.
Typically phraseology would include the holding instructions, with the approach time given in minutes past the hour.  For example:  "N123Z, hold at ZIPPO as published, expected approach time four zero."


text:
Do ATC say "Climb to XXXX on standard" or "Climb to standard XXXX" or something else?
Do ATC say "Climb to XXXX on standard" or "Climb to standard XXXX" or something else?
By "standard" I'm referring to altimeter pressure settings (set to standard pressure), but I'm not sure what the conventional phraseology is here for ATC instructions of this sort.
Any advice would be appreciated. Thank you so much.

That is extremely specific, I'm not going to attempt answering cause I don't have time but I want to include that each individual controller may say that common of a line in their own way.

Related: https://aviation.stackexchange.com/questions/39092/flflight-level-vs-altitude

Standard phraseology says that below transition level, the controller may use the phrase "altitude", or omit it completely, but it is still clear - eg/

BigJet 456, Climb and maintain 5000 feet

or

BigJet 456, Climb and maintain altitude 5000 feet

Of course, "altitude" or the use thereof implies that the controller has communicated (and the pilot has readback) the QNH.
Once above transition level, the phraseology calls for flight levels, and this is always using the standard pressure setting 1013 hPa / 29.92 in Hg

BigJet 456, Climb and maintain flight level 300

Examples inspired by ICAO standard phrasology, however it is important to remember that controllers and pilots quite often stray from exact standard phrasology.

ATC will say “Climb Flight Level xxx”.
There is no need to say “standard” because “Flight Level” is understood to mean standard pressure altimeter setting.

Thank you! If for some reason ATC needs to tell the pilot fo set the altimeter to standard pressure, how might they issue such an instruction?

@Pearl6527 They never do that. It's automatic (and required) when climbing above the transition altitude (for example, 18,000' in the U.S.).

@Pearl6527 ATC just specifies a flight level or an altitude. There's a standard protocol for switching to standard pressure and it's up to the pilot. Generally the change is always done on the standard pressure side, before transition alt on the way down, after transition alt on the way up. In the Canadian Arctic, there's an area called the Standard Pressure Region and there is no Transition Altitude at all, and it's Flight Levels right to surface, UNLESS you are departing or arriving at an airport. This is b/c there is no way to get local baro pressure in the middle of nowheresville.

@RalphJ I see. Are you never asked to set the altimeter to standard pressure below transition altitude?

@Pearl6527 Never.

@RalphJ Got it, thank you!

@Pearl6527, just to clarify, if you are descending below the transition altitude, or transiting sectors below it, (i.e. not expected to have local ATIS information...) ATC will generally always provide you with the local altimeter setting.  It is expected that pilots use it, but they don't specifically ask, or tell you to set it.

@MichaelHall Thank you!

An example of the US phraseology would be, "November one two three four climb and maintain one one thousand. Memphis altimeter three zero zero five."

How is this an example for standard pressure?

@Bianfable, for standard pressure the controller would simply say "Memphis altimeter two niner niner two."  Right?  ;)

@MichaelHall No, they would just say "climb flight level xxx" as explained in the other answers. There is no need to tell a pilot what pressure is standard.

@Bianfable, but this example uses 11K', that is not a flight level in the US.

P.S.  I know that we three all know how this works, and I am not defending this as the best most complete answer...

Oceanic areas would be the example where the assigned altitude is always given as a FL. The US AIP GEN 1.7 gives an exception to the use of transition altitude/level in US domestic airspace, but that exception is merely because that phraseology is never used by ATC, as you guys pointed out.


text:
How do pilots and flight attendants themselves refer to flight attendants casually?
If, say, a pilot is referring casually to a flight attendant friend (e.g. in an epithetical description), do they use "flight attendant"? It seems a bit of a mouthful.
For example:
A pilot is chatting to someone and they say something like "I have a flight attendant friend."
Would they simply use the complete phrase "flight attendant," or are there any other ways they might do it?
Thank you!

Typically, "flight attendant." It isn't generally shortened, the way that "first officer" can be shortened to "FO" (pronounced as two letters, not "foe") or simply to "pilot". In writing, the Flight Attendant position is often abbreviated to "FA", but it's rare to hear it spoken as those two letters.
The old single-word term "stewardess" hasn't been used in decades, and the shortened slang form of that, "stew," is heard pretty rarely; almost always it's simply "flight attendant."

At least in my experience, I hear "cabin crew" used frequently, as well.


text:
STRANGE VERY CLOSE MID AIR FLY BY
During a flight this week from Kefalonia, Greece to London Gatwick, about halfway through the flight. I looked out of my window on the right of the plane and was shocked to see a Silver plane, with it appeared 1 plume out of the back, pass our plane slightly below but very close, it disappeared past the window quickly but was alarmingly close.  How do I find out if this was a genuine aircraft.  Its colour didn't seem very normal. Thank you.
Flight Easyjet EZY6412 on 1st September.

For people that are not in the aviation industry, seeing traffic pass with the required minimum vertical separation (in the US generally 1,000') can be quite startling. Pilots and flight attendants see this regularly, so it's no big deal. For most people, seeing another aircraft only 1,000 below can look like an imminent collision, but is perfectly safe.

“How do I find out if this was a genuine aircraft”. I can assure you it was a genuine aircraft.

@Minsworld  You only saw one that happened to be offset on the  airway to pass to the side 1000 ft above or below.  Most of the traffic is perfectly centered on the airway thanks to the precision of GPS, and passes directly above or below where passengers can't see them.  If you could sit in the flight deck like in the old days, you'd freak out because they look like they're coming straight at you until they get a mile or so away and it becomes obvious they are above or below you.

How “close” do you estimate that was? What type of aircraft was it? An airliner or something a lot smaller?

I know that Flightradar24 has a history function in its paid subscriptions that enables you to view paths of past flights. I do not have this so unfortunately I will not be able to help here.
As stated in many comments, "close" encounters such as this are common, and as air traffic returns to its pre pandemic level, they will be very common. They pose no threat to safety as long as any of the multiple safety features built into aviation industry is active.
One contrail may suggest a single engine jet, or one that has engines relatively close to each other. There is a remote possibility that this jet was a military aircraft, which may not show on any flight trackers as they have the possibility to hide their presence from tracking systems. If it was a fighter jet, there was even less of a chance for a collision, due to the systems delivering highly accurate data of the surroundings to the pilot.

As someone who does have a paid subscription, there were two or three such encounters during the first hour of the flight alone.

The exact rules vary based on altitude, area, type of flight, etc, but the rule lost likely applicable in your case is that flights are on flight levels (FL) which are multiples of ten, either an odd multiple of ten (FL270, FL290, FL310…) if they have a heading between 0 and 179 degrees, or an even multiple of ten (FL260, FL280, FL300…) otherwise.
Flight levels are multiples of 100 feet.
So you could have one flight heading west or north-west like yours on FL260 (26000 feet) while another flight is heading east on FL250 (25000 feet). That’s a difference of 1000 feet, roughly 300m.
If both planes were heading in (roughly) the same direction, it would be double.
Given the size of aircraft, one flying 300m from yours may seem extremely close, but there’s no risk there, this is just regular operations.
Another possibility if the aircraft was A LOT closer (but probably a lot smaller) is that there was some kind of situation (e.g. radio malfunction) and a military jet was sent to check if everything was alright. But that’s quite the rare occurrence, and since you apparently got to your destination without trouble, nothing bad happened.


text:
Confused about this Pressure Altitude vs True Altitude Question
The standard question on a knowledge test:
"Under which condition will pressure altitude be equal to true altitude?"
The answer is: "when atmospheric conditions exist, i.e., 29.92" Hg and 15 degrees C at sea level."
What I'm not understanding fully is what the temperature at sea level has to do with pressure altitude.
For example, say the sea level pressure is 29.92" Hg but the temperature at sea level is 20 degrees.
Wouldn't pressure altitude still equal true altitude?

What is the definition of true altitude?

Not an expert, but I believe the true answer is "when sea level pressure is 29.92 inHg and the temperature at your altitude matches the temperature modeled for that altitude in the International Standard Atmosphere."

Might be a typo but the correct answer is "when STANDARD atmospheric conditions exist, at all altitudes below the aircraft." Even the lapse rate can make pressure altitude differ significantly from true altitude.

The answer in your book is a bit misleading (but mostly correct for all practical purposes). The right answer would be "when the pressure at that altitude equals the pressure you'd find at the same altitude in the standard atmosphere".
The existence of standard atmospheric conditions is sufficient but not necessary for true altitude to be equal to pressure altitude. In other words, pressure altitude and true altitude could be equal even if standard conditions are not present.
So, in your example, if sea level pressure is 29.92" Hg and the temperature is 20 degrees, pressure altitude and true altitude are equal provided that the temperature lapse rate has a higher (specific) value than the one in the standard atmosphere.

Pressure of the air above you is affected by both non-standard pressure and non-standard temperature.  "From high to low, look out below" is a way of remembering that flying from high pressure to low pressure and your true altitude will decrease.  It is also true with temperature.
What is interesting to me with this question is the altimeter setting is set for both non-standard pressure and non-standard temperature at the field.  As soon as you increase altitude, your true altitude starts to differ from the pressure altitude read on the altimeter.  I realized, though, the question doesn't assume you are at an airfield but are flying in the air.
The US AIM (7-3-1) has a great discussion on how cold weather affects pressure altitude.  The FAA has also issued special procedures for airports with obstacle issues in cold weather.  They are called Cold Weather Restricted Airports.  You can find a current listing at the bottom of this FAA page.
https://www.faa.gov/air_traffic/flight_info/aeronav/digital_products/dtpp/search/

The pressure altitude will be equal to the true altitude (I understand this to be defined as the geopotential height above the mean sea level) when the pressure at that true altitude is equal to the pressure derived from the ICAO Standard Atmosphere model (described in ICAO Doc 7488) for that true altitude.


text:
What if i dont want any crop dusting done near my home simply because of the cancer causing affects from the chemicals being spayed right on top of me
I have 8 acres and I am surrounded by farmland that gets sprayed regularly every year! Twice while driving down my road, the plane flew right over top of me and splattered my entire car with spray chemicals! And once while working in my yard, I smelled it first, then I felt a wet light mistyspray on my arms, and was visible on my jeans!! I don't want any crop dusting near my property for that reason alone..can I stop them, there are other ways of application, I feel threatened by these health hazardous chemicals on top of me year after year..what can I do to stop them?

This is primarily a legal problem and not an aviation problem.

How do you know these chemicals are "health hazardous"? Do you even know what the chemicals are? You have to find out what is being sprayed, and document the dates and times, and provide photos or witnesses. Then you can complain to your local lawman.

I agree this is not an aviation question.  But as with many of these things, the very first step I believe is to identify the landowner and discuss your concerns with them.  It is possible you'll get the "whatever."  But its also possible they'll be concerned and feel it is their responsibility to discuss it with the application company that they aren't being considerate enough of neighbors.  And if you don't get satisfaction and decide to take it up with your township or county, it will matter to them that you already made an attempt to clear things up with the owner and were rebuffed.

Peggy, it may not be worth your effort now, but you could edit your question to ask about aviation regulations specific to crop dusting and get the question reopened in case you think there might be benefits in getting any additional perspective on your issue.  The existing answer is ready-made for such an edit, and could be accepted unless somebody else chimes in with something better.  A succinct, regulation based Q&A that is searchable might be a good thing to have for the record...


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Will a heavier aircraft be more efficient at high speeds(cruise)?
Since heavier aircraft have more mass and inertia, they will have less drag because it will be easier for them to push through the air so does that mean that we can achieve the same cruise speed with less engine power=more efficiency?

Wrong. Drag has nothing to do with mass or inertia. Drag is an aerodynamic force, caused by the force created by air molecules impacting and bouncing from the surface of the aircraft.  The mass of the air molecules matters, but aircraft mass or inertia has nothing to do with it.

I think he wants to say that the aircraft will have more energy so it will be "easier to push through the air" and there will be less energy wasted in opposing drag

All the rest being equal, more mass implies more power needed to accelerate or decelerate the aircraft and more lift and drag to keep if flying

This works for projectiles like bullets which "store" kinetic energy and don't need lift. If you need lift and can store the energy as height (glider) it roughly cancels. For any other energy source weight is bad, although a plane so flimsy it breaks up (Helios) or planes that can be blown away while parked aren't exactly good either.

Inertia is defined by Oxford languages as

a property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force.

The key here is "the external force".
The equation for drag force is
$F_d=\frac12ρv^2c_dA$
While you are correct in that the drag force is linked into the interia as it is an external force acting on an object, you can see that drag equation does not have the mass of the (flying) object in it.
To maintain straight and level flight, the drag has to be matched by engine thrust, inertia has no effect here because the plane is not accelerating. In that sense the mass of the aircraft is insignificant.
However, as we know the aircraft needs lift to stay in the air, and the more mass it has, the more lift is needed. To put it simply, that lift is ultimately generated by pushing air downwards by wings, rotors etc, and for that we ultimately need engine power. So the heavier the plane, the more power is needed for cruise.
It might be more efficient per unit mass to fly a heavier plane up to a certain point, but it is not because of inertia.

Inertia is a property related to acceleration, as in Newton’s first law $F = m \cdot a$. If we want to change the current velocity of the aeroplane, we need more force to do so when inertia is higher.
Aerodynamic drag is a force proportional to velocity. At any constant velocity the drag remains constant, no matter what the inertia of the plane is.

..does that mean that we can achieve the same cruise speed with less engine power..

Heavy aeroplanes require more thrust and power:

To get to cruise speed, it has taken more force to accelerate the higher inertia. The plane's kinetic energy content $E_{kin} = ½mV^2$ is higher at a higher mass m.
At the same cruise speed, a heavy aeroplane requires more thrust than the same light aeroplane in the same cruise conditions. It requires more lift, which increases drag D = $C_D \cdot ½ \rho V^2 \cdot S$, with $C_D = C_{D0} + k{C_L}^2$ (k = a constant based on aeroplane geometry)

"a heavy aeroplane requires the same thrust as the same light aeroplane".
It would actually require more lift, more drag and therefore more thrust

@sophit Indeed, have amended the answer, thanks for that. Not a good idea to post an answer after a transcontinental flight.

Eh eh eh, no :-)

Will a heavier aircraft be more efficient at high speeds(cruise)?

If the aircraft is a glider, then yes.  Gliders very often carry water ballast to increase their weight, and thus reduce their sink rate and increase their efficiency (expressed in terms of glide ratio, or approximately, L/D ratio1), at a given, high, target airspeed that is well above the unballasted, still-air best-glide-angle speed.
Footnotes:

Only in constant-airspeed flight in still air does glide ratio exactly equal L/D ratio.  But regardless of the details, the point remains that increasing the mass of a glider allows flight at a higher angle-of-attack, and also often a lower sink rate, and thus a higher glide ratio relative to the ground, for flight at a given high airspeed.

Interesting point of view


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Safety factor in airliner design
I am currently working on a baseline configuration and initial sizing for a conventional airliner with 90 passengers.
The FAA states that an average passenger weighs approx. 80kg. When calculating my total passenger weight, should I include a safety factor or would it not be needed since the weight variance with such a large aircraft will be small?

Related: How do airlines handle uncertainty in passenger weight for weight and balance calculations?

Safety factor is not applied to the payload.
Once the biggest loadcase for each component of the airframe has been defined, a safety factor is applied to these loads and the structure is sized consequently.
For example, for a standard jetliner the OEI is normally the designing case for the vertical stabiliser. Once the aerodynamic load on the vertical stabiliser has been calculated for that case, this load is multiplied by the safety factor and then used to size the structure of the vertical fin.

the weight variance with such a large aircraft will be small?

Aircraft's airframes are extremely efficient and payload is therefore not a small part of the MTOW: for an A350, payload can be as high as 68000kg with a MTOW of 316000kg i.e. some 20% of the MTOW.


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What is considered a positive rate?
I'm a beginner pilot, and i am trying to perfect my takeoff. What vertical speed is considered a positive rate in a Boeing 747?
Thanks in Advance

A positive rate is anything above 0.

Positive rate is any vertical speed that you are climbing.  i.e. greater than zero.
You don't want to raise the gear too early in the takeoff.  If you did and settled back down on the runway you would damage and/or destroy the aircraft.  It's best to be climbing above 100 to 200 feet AGL before raising the gear.  Even at that altitude, if you experience a windshear/microburst you may find that you are skidding on the ground again.
The arguments for getting the gear up right away are about drag improving climb performance with the gear up.
The arguments for keeping the gear down for a short period of time include windshear/microburst or poor takeoff technique.  If the airplane touches down again, I would much rather be on the gear and use the shock struts to absorb some energy during the impact.

Another issue with raising gear early is that for some aircraft there is an increase in drag during the transition.  For example gear doors that are closed when the gear is down and up have to open during transition and thus increase drag.  Not something you would want as you leave the runway.


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How to determine the size and placement distance of vertical and horizontal stabilisers given the size of my wing? (it's a foamular250 glider)

If the wing has a Chord of 150 mm and a span of 800 mm, what about the distance to the tail? anf the size of horizontal and vertical stabilizer?

Could it be that you find the answers to this question helpful?

This answer could be helpful as well

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer.

Well, you size your vertical and horizontal stabilizers based on their distance from the center of gravity.

torque around the the center of gravity is force × distance

So the first question is how long the fuselage will be.  Remember that the tail torque must always be able to be stronger than torque produced by the wing and/or fuselage under all possible flight conditions including stalls.
Other considerations are:
1.  pitching moments at various angles of attack
2.  distance of wing center of pressure from center of gravity
3.  how aerobatic will your plane be (how many G forces can it withstand) - size of rudder and elevator/stabilator control surfaces
4.  thrust line and magnitude
Size and throw of elevator and rudder will also be critical.  It is recommended to use an existing design as a starting point.  Plenty of 800 mm gliders can be found at the hobby store.